Brake mechanism



Aug. 20, 1940. c. c. FARMER 2,211,888

BRAKE MECHANISM Filed July 9, 1938 5 Sheets-Sheet 1 INVENTOR CLYDE C.FARMER ATTORNEY Aug. 20, 1940. c. c. FARMER BRAKE MECHANISM Filed July9, 1938 5 Sheets-Sheet 2 INVENTOR c LYDE c. FARMER BY R 3 Ah ATTORNEYWmfr 5 sneaks-sheet s c. c. FARMER BRAKE MECHANISM Filed July 9, 193aAug. 20, 1940.

m v hw INVENTOR CLYDE C. FAHMEF! ATTORNEY wm NM 5 NM gun "HIE Ll 20, 194c. c. FARMER 2,211,888

BRAKE MECHANISM Filed July 9, 1938 5 Sheets-Sheet 4 C LYDE C. FARMEHATTORNEY Aug. 20, 1940. c, c, FARMER 2,211,888

BRAKE MECHANISM INVENTOR CLYDE C. FAHMER 1 ATTORN EY Patented Aug. 20,1940 .UNITED STATES PATENT OFFICE name nmcnsmsrr Application July 9,1938, Serial No. 218,384

25 Claims.

This invention relates to brake mechanism for vehicles and moreparticularly tothe type em bodying annular rotatable and non-rotatablefriction braking elements adapted upon frictional interengagement toeflect-braking of one or more of the wheels of the vehicle. 7

One object of the invention is to provide an improved brake mechanism ofthe above type particularly adapted for use on the trucks of railwayvehicles for braking the wheels thereof.

Another object of the invention is to provide an improved brakemechanism of the above type in which the major portion of the weight ofthe mechanism is carried by the truck frame as sprung weight, so as tominimize damage to the truck wheels or other umprung parts of the truckdue to the wheels striking irregularities in the rails, such as at railjoints, or the like.

In a brake mechanism of the type comprising annular friction brakingelements some of which are carried by the truck frame and the others bythe wheels or axle of the truck, it will be evident that the elementscarried by the frame will move vertically with the frame relative to theelements associated with the wheels and axle, due to changes in loadcarried by the truck or due to vibration of the truck on the trackrails, and will therefore at difierent times or' under differentconditions assume various positions eccentric to the elements carried bythe wheels or axle. It is desirable that the annular braking elementscarried by the truck frame be in concentric relation with those carriedby the wheels or axle at the time such elements are moved intofrictional braking engagement and another object of the invention istherefore to provide improved means for centralizing'the brakingelements carried by the truck frame with those associated with the wheeland axle assembly at the time said braking elements are moved intofrictional engagement for eflzecting braking of the trucli wheels.

Another object of the invention is to provide an improved disc brakemechanism of the above type comprising two braking units so constructedand arranged as to apply braking force to a wheel and axle assembly attwo spaced portions thereof and having a single torque connection withthe truck frame adjacent its transverse cen-' ter so that duringbraking, forces will not "be applied to the frame to cause sidewisetipping thereof and so that rocking of the frame from side to side, dueto unevenness of the track or the like, will be relative to andtherefore have no effect upon the operation of the brake mechanism.

Another object of the invention is to provide an improved brakemechanism of the above type so constructed and arranged that the truckframe is never subjected to the forces provided for effecting braking ofthe truck; the truck frame according to the invention being subject onlyto the forces required to hold the non-rotatable braking elementsagainst rotation during braking, which forces are relatively smallcompared to those which are employed to efiect the actual braking.

Other objects and advantages will be apparent from the following moredetailed description of the invention.

In the accompanying drawings: Fig. 1 is a plan view of a portion of arailway vehicle truck showing, partly in plan and partly in section, theinvention applied thereto; Figs. 2, 3 and 4' are sectional views takensubstantially on the lines 2-2, 3-3 and 44 in Fi 1; Fig. 5 is a sec--tional view taken on the line 55 in Fig. 4; Fig. 6 is a vertical,sectional view of a spring supporting device shown in elevation in Figs.2 and 4; Fig. '7 is a side elevational view of a portion of one side ofa vehicle truck with which the improved brake mechanism is associatedfor the purpose of illustration; Fig. 8 is a view sim-; ilar to aportion of Fig. 1 and illustrating a modification of the invention; andFig. 9 is a sectional view taken substantially on the line 99 in Fig. 8.

As shown in the drawings, the improved brake mechanism is associatedwith a truck of the type employed under railway vehicles and which, forthe purpose of illustration, may comprise a truck frame In having theusual spaced side members ll connected together by transverselyextending end membersiZ and transoms I3.

The side members H are provided at their opposite ends with the usualdepending, spaced pedestals l4 slidably mounted on journal boxes l5. Anaxle I6, at each end of the truck is journaled 'at its ends in anoppoitely disposed pair of journal boxes l5, while rigidly secured tosaid axle in any desired manner and in the usual spaced relation are apair of wheels 11 adapted to roll on rails l8.

,An equalizer bar [9 is disposed at each side. of thetruck frame withits ends resting on the top of the journal boxes l5 for support, whileinterposed between said equalizer bars and the .truckside members H aresprings 20 for re iii) siliently supporting the truck frame II from thewheel and axle assembly.

Only a portion of the vehicle truck above described is shown in thedrawings, but the construction of such trucks are so well known that theshowing is deemed sumcient for a clear understanding of the invention.It is desired however to point out that since the truck frame ll isresiliently supported by springs 2| from the assembly of axle II andwheels l1, said frame is capable of movement vertically relative to saidassembly and will therefore assume various elevated positions withrespect to said assembly due to vibration of the frame caused byirregularities in the track rails or the like or due to differentdegrees of load supported by the truck.

According to the invention, the improved disc brake mechanism isassociated partly with the truck wheel and axle assembly and partly withthe truck frame II; the major portion of the weight of said mechanismbeing, however, carried by the truck frame as sprung weight, in order tominimize wear and possible damage to the truck wheels and other unsprungparts of the truck, due to the wheels en8l8 8 irregularities in thetrack rails such as at rail joints, or the like.

The improved brake mechanism comprises two. like braking units arrangedin spaced relation between the wheels il. Each of these braking unitscomprises an annular rotatable friction braking element 2| and twoannular non-rotatable friction braking elements 22. All of these brakingelements encircle the axle It with one of the nonrotatable elements 22disposed at either side of each of the rotatable elements 2i, therotatable elements 2i being provided on their opposite faces withradially arranged braking surfaces adapted to be frictionally engaged bythe adjacent surfaces of the non-rotatable elements for braking thewheels i1.

Two oppositely disposed sleeves or collars 23 are rigidly secured to theaxle II in any desired manner, one of said sleeves being disposedadjacent one of the wheels l1 while the other sleeve is disposedadjacent the opposite wheel, Each of the sleeves 23 is provided adjacentits inner end with an annular flange 24 to which is secured by bolts 25in concentric relation with wheels i1, one of the rotatable brakingelements 2|, whereby said element is secured to rotate with said wheels.

Outside of the flange 24 each sleeve 23 is proyided with a. cylindricalcentering portion 2 concentric with the rotatable element carried by thesleeve.

Each of the rotatable elements 2i is preferably made in two,substantially semi-circular sections secured to the flange 24 inoppositely disposed, preferably abutting relation to facilitate assemblyand replacement thereof on the sleeve 23.

Each of the non-rotatable elements 22, which is supported from the frameII by means to be later described, is provided with a central opening ofsuch diameter as to permit vertical movement thereof with the truckframe ll relative to the associated rotatable element 2| and axle II aswill be later brought out in greater detail.

A cradle or brake supporting frame-like structure 21' is disposedbetween one side of axle II and one of the transverse members of thetruck frame, preferably the transom It. The cradle 21 comprises a backportion 22 which is pfvotally connected intermediate its ends to atransverse central portion of transom ii at substantially a universalconnection such as a ball and socket joint 20. By reason of this balland socket connection it will be evident that the truck frame ll mayrock sldewise relative to the cradle 21, while the cradle may move withthe wheels relative to the truck frame as the wheels followirregularities in the track rails ll, or the like.

Zlhe cradle 21 is provided at each end of the back portion 2. with apair of spaced, substantially horizontally extending arms II and ii, thearms 20 being longer than the arms II and projecting over the top ofaxle ll, while the shorter arms ll are disposed at a level below andterminate substantially beneath said axle. Itwillbenotedthatbothsetsofarmsfl and ii are spaced from the top andbottom of axle ll so as to permit movement of the cradle in a. verticaldirection relative to the axle without enc sement between said arms andsaid axle.

ATbarflextendsbetweenandissecuredby bolts utotheendofthelongerarms 28disposed above the axle ll, each of said arms being provided with a slotarranged substantially radially with respect to axle II to receive theend portions oftheleg32' ofsaidbar. AlikeTbar 24 extends betweenandissecured bybolts lltotbeshort arms ll below the axle II, the bar 24being so arranged that the leg portion 24' thereof is opposite to and inalignment with that of thebar 22.

Each of the non-rotatable elements 22 is preferably made in two, like,substantially semi-circular sections arranged opposite to each other inabutting relation, with the two sections rigidly secured together bybolts 26 provided through flanges 81 which extend from the facu of thesections opposite the braking faces thereof.

Each section of each non-rotatable element 22 is provided at its endswith a portion 28 extending radially outwardly therefrom. In the end ofeach portion ll there is a notch, the notch in the two cooperatingportions of each two sections.

when secured together, acting to provide a slot to slldably receive theleg portion 32 or 24' of oneoftherbarsfl or. Itwillbenotedthat each ofthe non-rotatable elements is provided with two such notches which arediametrically opposite and said elements are adapted to be mounted incradle 21 so that the leg 22' of 1' bar 22 is in one of said notcheswhile the leg N of T bar 24 is in the other of said notches, whereby thenon-rotatable elements are supported by and slidable on said bars in thedirection towards and away from the rotatable braking elements 2|.Engagement between the 1' bars 22 and II and the non-rotatable elements22 is also adapted to hold said elements against turning during braking,which will be later described.

Each of the longer arms II is provided adjacent its outer end with apair of upstanding, spaced ears 2|. One end of a stem 0 of a springsupporting device II is disposed between the ears 2! on each arm II andis pivotally connected thereto by a pin 42. Each spring supportingdevice ll comprises a casing the upper end of which is closed by a cover42 provided on its outer face with a pair of upstanding ears M which arepivotally connected through the medium of a pin 4! to any suitableportion of the truck frame ll such as a member extending between andsecured at its opposite ends to the side frames I I.

The cradle 21 is thus connected to and normally supported from the frameII at three points, namely, the ball and socket connection 2| at one endand through the two spring supporting devices ii at the opposite end. i

The pivotal connections between devices 4| and the cradle 21 and frameIII are so arranged as to permit movement of the connected end of cradle21 with the axle l6 transversely of the truck relative to the frame IIIwhile sufficient looseness is provided in such pivotal connections as topermit movement of the lower end of the devices in the direction of thelength of the truck upon vertical movement of the arms 30 relative toaxle l6, under conditions which will be later brought out.

As shown in Fig. 6 of thedrawings, the stem 40 of each of the springsupporting devices 4| extends into the device and therein is providedwith an outwardly extending flange portion 58 be-' tween which and thelower end of the casing of the device there is provided a spring 41which acts to move the stem 40 inwardly of the device. The springs 41 inthe two devices 4| are so designed that the combined force of both, whenin the position shown in Fig. 6, is adapted to Just counterbalance theweight of the connected portion of cradle 21 and a portion of the weightof the brake mechanism carried by said cradle.

The cover 43 of each spring supporting device 4| is provided on itsinner face with a depending centrally located boss 48 having an axialbore in which there is secured in any desired manner one end of a pin 49which extends through a bore 50 provided lengthwise of the stem 40. Thelower end of each pin 49 is provided with a head 5| which is disposed tomove in a counterbore 52 provided in the stem 40 below the bore 50.

Slidably mounted on the stem 49 in each of the spring supporting devices4| are two oppositely disposed spring seats 53 and 54 between whichthere is interposed a coil spring 55 which encircles the pin 49 andwhich is under compression. In the normal position of the parts of eachspring supporting device 4| the spring 'seat 54 engages the bottom ofthe bore 50, while the spring seat 53 engages the end of the boss 48,thereby confining the associated coil spring 55 under pressure betweensaid seats.

Encircling the boss 48 within each of the spring supporting devices 4|is. a ring 51 which is secured to flange 56 on the inner end of the stem40. The ring 51 has a central opening of smaller diameter than that ofthe bore 50 so as to provide a shoulder for engagement with the springseat 53.

It is well known that as a car truck moves along track rails and strikesirregularities therein, the truck frame tends to bounce or movevertically relative to the wheel and axle assembly. It will be evidentthat under such conditions the end of the cradle 21 carried by springs41 will also tend tomove vertically relative to the truck frame.However, in case the end of cradle 21 supported by the spring supportingdevices 4| tends to move upwardly relative to the truck frame l0 thismovement is transmitted through the stems 40 of the supporting devicesto the spring seats 54 and acts to urgesaid seats against the pressureof the springs 55 the opposite ends of which are fixed against movementdue to the spring seats 53 engaging the ends of the bosses 48. As aresult, the force of the two springs 55 becomes immediately effective tooppose or dampen such movement and return the cradle to its normalposition with respect to the truck frame.

In case the cradle 21 tends to move downwardly relative to the truckframe the rings 51 in the spring supporting devices 4| pick up thespring seats 53 and love them against the pressure of the springs 55 thelower ends of which are at this time held in a. fixed position by theengagement of I said cradle to its normal position with respect to e thetruck frame It.

In other words, the two springs 55 are provided to oppose or dampenmovement of the cradle 21 out of its normal position with respect -tothe frame l0, whereby the cradle is substantially held againstoscillation relative to the truck frame when the brakes on the vehicleare released and the parts of the mechanism are in their normal positionsupported by the truck frame.

A cross-head 58, disposed at the transom side of axle I6 is mounted toslide in a substantial horizontal direction in suitable parallel slots59 provided in the adjacent faces of each set of arms 30 and 31. Each ofthe cross-heads 58 is provided in the face adjacent axle l6 with tworollers 60 disposed one above the other the same distance from the axisof the non-rotatable elements 22 and spaced apart a distance equal to orjust slightly exceeding the diameter of the cylindrical centeringportion 26 of the adjacent sleeve 23 on axle I6. Each of the cross-headsis cut out between the rollers 60 to receive the axle IS withoutengagement between the cross-head and axle.

In the drawing, the cross-head's 58 are shown in their normal position,that is, the position 00- cupied when the brakes on the truck arereleased, and it will be noted that there is a certain amount ofclearance between rollers and the sleeves 23 on the axle l5, so that thecradle 21 and the parts I of the brake mechanism carried thereby arefree to be moved with the truck frame ID by the spring supportingdevices 4| relative to the axle I6.

In Fig. 2 of the drawings, the same clearance space is shown betweeneach of the rollers 60 and sleeves 23. This condition will only beobtained when the truck is in a substantially, semi-loaded condition. Incase the truck frame In is in its empty condition it will be elevatedabove the position shown with respectto axle l6 and sleeves 23 in whichcase there will be less clearance space between the lower rollers 80 andsleeves 23 than between the upper rollers 50 and said sleeves, while incase the truck frame I0 is in the position assumed supporting a fullyloaded vehicle the clearance space between the upper rollers 60 andsleeves 23 will be less than between the lower rollers and said sleeves.In otherwords, the normal positions of the rollers 60 with respect tothe cylindrical portions 26 of sleeves. 23 will vary with the loaded andhence elevated position of the truck frame.

When an application of the brakes is effected, as will be laterdescribed, the cross-heads 58 are adapted to be moved from their normalposition, just described, in the direction of the sleeves 23 to acentering position in which the rollers 50 engage substantiallydiametrically opposite portions of the cylindrical portions 26 of thesleeves 25 in which position the non-rotatable elements 22 are adaptedto be in substantial, concentric braking relation with the rotatableelements 2|.

In case the cross-heads 58 are in the position shown in the drawings atthe time an application of brakes is effected, the movement thereof tothe centering position just described will be merely relative to thesleeves 23 on axle l8. However, if at this time the cross-heads 58 arein a position above that shown, the lowermost rollers 50 will engage thecylindrical portions 2! of the sleeves 2s somewhere between the bottomand mid portions thereofand as said rollers are then forced against thesleeves. by means to be later described, said rollers roll or arepropelled along the peripheries of the sleeves 'in .a downwardlydirection to their centering position and during such movement act torock-.the era'- dle 21 in a clockwise direction, as viewedin Fig. 2 oithe drawings, about the connection 22 with the truck frame, and therebydraw the nonrotatable elements 2! into concentric relation with therotatable elements 2| In case the cross-heads 58 are in a position belowthat shown at the time an application of the brakes is initiated, thetopmost rollers 00 will first engage the sleeves 22 and then act uponmovement along the peripheries of portions 2| of said sleeves to rockthe cradle 21 in a direction opposite to that above described andthereby move the non rotatable elements 22 upwardly into concentricrelation with the rotatable elements 2|.

The cradle 21 will be rocked relative to the truck frame II as justdescribed a degree which depends upon the elevated position or the truckframe, but regardless of this degreerwhen the rollers 60 obtain theircentering position the non-rotatable elements 22 will bein concentricrelation with the rotatable elements 2| and will be held in suchrelation by the upper and lower rollers Gil cooperating withsubstantially diametrically opposite parts 0! the cylindrical portions26 of sleeves 22.

When the cradle 21 is rocked relative to the truck frame It as justdescribed, such movement is opposed by either one or both of the springs41 and 55 in the supporting devices ll, depending upon the direction ofrocking, but this is immaterial.

When the brakes are released after an application, as will be laterdescribed, the cross-heads II are adapted to be drawn from theircentering position back to their normal position in which the rollers 60are disengaged from the sleeves 22 to permit the springs 41 to againsupport the associated end of the cradle 21 from the truck frame.

A fluid pressure controlled cylinder device 22 is provided forcontrolling movement of the cross-heads is. This cylinder device ismounted on a shelf 62 extending outwardly from the back portion 28 ofthe cradle between the arms 22 and comprises a casing containing apiston 24 having at one side a pressure chamber 25 and at the oppositeside a chamber 60 which is open to the atmosphere in any desired manneras by way of a release port 90.

The piston 64 is provided with a rod '1 extending through thenon-pressure chamber and a suitable opening in the end wall thereofwhile in said chamber there is provided a return spring I acting on saidpiston for moving it to its normal position shown in the drawings. Thepiston u is provided on its non-pressure face with an annular sealingbead ll adapted in one position of the piston to efiect sealingengagement with a gasket 92.

The end of the piston rod 1 is pivotally connected to the center of anequalizer bar I through the medium of a pin ll, while each end of saidbar is operatively connected through a rod H to one end of asubstantially vertically disposed lever 12. Each of the levers I2 ispivotally connected by a pin 12 midway between its ends to the cradle21, while the opposite end of each'of said levers is pivotally connectedto the: piston 04 is adapted to be moved from the position shown intosealing enga m nt w gasket 22 and during such movement is adapted toactuate the equalizer bar I and therebyiturn the levers 12 in acounterclockwise direction for moving the cross-heads II from theposition shown in the drawings to their centering position abovedescribed. A stop I is provided in each of the arms 2. and II of thecradle 21 adapted to be engaged by the cross-heads II in case oneobtains the centering position ahead of the other to ensure the otherobtaining said position by the time the actuating piston ll engages thegasket l2.

Each of the non-rotatable elements 22 is provided with two diametricallyopposite pairs of outstanding lugs ll, one pair directly above the axleIt and the other pair below the axle, and pivotally connected to eachpair oi these lugs is one end of a substantially horizontally disposedbrake lever It. i The opposite ends of the two brake leversconnected toeach oi the outside non-rotatable elements 22 are pivotally connectedthrough the medium of pins II to oppositely disposed projections llextending from the cradle 21, while the corresponding ends of the twobrake levers I. connected to each of the inside non-rotatable elements22 are pivotally connected through the medium 01' suitable links 12 tothe opposite ends of a vertically disposed equalizer lever III. In eachbrake unit the levers ll connected to both the top and bottom portionsof the twonon-rotatable elements are pivotally connected togetherintermediate their ends by means of links II which are U- shaped inorder to bridge without engaging the intermediate rotatable brakingelement 2!.

A pair of oppositely disposed brake cylinder devices 82 are secured tothe back portion is of the cradle 21, one of said brake cylinder devicesbeing provided for controlling the operation of each of the equalizerlevers ll.

Each of the brake cylinder devices 22 is disposed adjacent one end ofthe cradle substantially midway between the top and bottom thereof andcomprises a piston I2 having at one side a pressure chamber 24 and atthe opposite side a non-pressure chamber II which is open to theatmosphere in any suitable manner. Eachof the pistons 02 is providedwith a piston rod ll extending through the non-pressure chamber II andthe end of the casing and pivotally connected at its outer end throughthe medium 01' a pin ll to one of the equalizer levers ll midway betweenthe ends thereof. A release spring II is provided in the non-pressurechamber 22 of each brake cylinder device and acts on the brake cylinderpiston 22 for urging it to its release position shown in the drawings.

The pressure chamber 24 in both brake cylinder devices 22 is connectedto a common type it which is connected by a pipe I to a passage 0! inthe centralizing cylinder, which passage is adapted to be opened to thepressure chamber 85 when the centralizing piston 64 is in engagementwith gasket 92.

The pressure chamber 65 in the centralizing pipe in order to effect anapplication of the brakes of the trucks and to release fluid underpressure from the said pipe in order to eifect a release of the brakes.

Operation Let it be assumed that the pipe 96 is vented by way of atriple valve device (not shown) or in any other desired manner. With thepipe 96 vented spring 69 in the centralizing cylinder device 62 will beacting to hold the piston 94 in the position shown in the drawings andthereby acting through the piston rod 61, equalizer bar 69, rods H andlevers 12 to hold the cross-heads 69 in their normal position in whichthe rollers 60 are moved away from the sleeves 29. With the cross-heads59 in their normal position the cradle 21 will be supported in itsnormal position from the truck frame I9 through the medium of the balland socket connection 29 and by springs 41 in the supporting devices 4|and will therefore move with and occupy positions corresponding to thoseassumed by the truck frame III with respect to the axle 6.

With the centralizing piston 64 in its release position, shown in thedrawings, the pressure chamber 84 in both brake cylinder devices 92 isvented through pipes 99 and 94 and passage 96 in the centralizingcylinder device to the nonpressure chamber 66 and from thence throughvent passage 90 in said device to the atmosphere, so that the brakecylinder release springs 96 are permitted to act to hold the brakecylinder pistons 83 and thereby the piston rods 96, equalizer levers 89,links 19, brake levers 16 and the connected non-rotatable brakingelements 22 in their release position, in which said elements are spacedfrom the rotatable elements 2|, as shown in the drawings and as will bemore fully described later in connection with effecting a release of thebrakes after an application. With the nonrotatable elements 22 thusspaced from the rotatable elements 2|, said rotatable elements are freeto rotate with the axle 6 and thereby with the wheels I! as the truckmoves along rails i9.

If it is desired to retard or stop rotation of wheels i1 or in otherwords to brake the truck when it is moving along the rails l8, fluidunder pressure is supplied to the pipe 96 by the operation of a triplevalve device or the like.

Fluid pressure thus supplied to pipe 96 flows to pressure chamber 65 inthe centralizing device 62 and therein acts to move the piston 64 in thedirection against spring 68. This movement of the piston 64 and therebyof the rod 6'! acts to operate the equalizer bar 69 and connecting rodsII to turn the levers 12 in a counterclockwise direction, as viewed inFig. 2 of the drawings. This movement of levers I2 slides the crossheads58 forward toward axle l6 bringing the rollers 60 into cooperatingrelation with the centralizing cylindrical parts 26 of the sleeves 23for centralizing the non-rotatable element 22 with respect to therotatable elements 2| as hereinbefore described. This centralizingaction is completed by. the time the centralizing piston 64 moves pastthe brake cylinder port 95 and into sealing engagement with the gasket90.

when the centralizing piston 94 moves past and thus connects thebrake'cylinder port 99 tovthe pressure chamber 9|, fluid under pressuresupplied to said chamber then flows to pipe 94 and from thence throughpipe 99 to the brake cylinder devices 92.

Fluid under pressure thus supplied to each of the brake cylinder devices92 acts on the piston 99 therein to move said piston against the releasespring 99 and thereby operate the connected equalizer lever 99 to movethe ends of the connected brake levers II in such a direction as to"move the opposite ends of said levers and thereby the connectednon-rotatable element 22 toward and into engagement with the brakingface of the adjacent rotatable element 2|. When the inside non-rotatableelements 22 are thus moved apart and into engagement with the adjacentrotatable elements 2|, said rotatable elements become a fixed fulcrumfor the inside levers 16,

.so that further operation of said levers then actsthrough the links 9|to move the outside brake levers 16 in such a direction as to shift theoutside or connected-non-rotatable elements 22 into engagement with theadjacent rotatable elements 2|. After the non-rotatable elements 22 ineach brake unit are thus moved into engagement with the opp site facesof the rotatable element 2|, further pressure applied by the brakecylinder devices to the inside levers 16 then acts to force thenon-rotatable elements 22 into frictional contact with the rotatableelements 2| with such force as to effect braking of the rotatableelements and thereby of the axle I6 and wheels for retarding or stoppingrotation of said wheels, as desired. v

The degree of pressure with which the nonrotatable elements 22 are thusforced into frictional engagement with the rotatable elements 2| can bevaried as desired by varying the pressure of fluid supplied to the brakecylinder pressure chambers 94, in the usual manner, whereby any desiredrate of retardation may be obtained.

Each of the rotatable elements 2| is provided with a plurality of spacedradial bores I 69 open at the periphery of the element and connected attheir inner ends with cross passages ||i| which open to the oppositefaces of said element, and through these bores and passages air isadapted to constantly circulate when said element is rotating. Thiscirculation of air between the braking faces of the rotatable elements2| is adapted to carry away heat created by the frictional brakingengagement of the non-rotatable elements 22, in order to maintain thetemperature of said elements at a suiliciently low degree to provideeflicient braking.

It will be noted that in this improved structure the truck frame I9 isnot subjected during braking to the relatively high pressure developedin the brake cylinder devices 92 and transmitted to the non-rotatableelements 22 as in conventional type of brake equipment. The truck framel6 merely acts through the medium of the ball and socket connection 29to support one end of the cradle 21 and to hold the non-rotatableelements against turning during braking, The force required to hold thenon-rotatable elements against turning is however only a relativelysmall portion of that developed in the brake cylinder devices and sincethe torque arm between said elements and the ball and socket connection29 is relatively long the force applied to the truck frame is even less.This is very desirable in that tional type of brake equipment in whichbrac-.

ing in one form or another is required for resisting braking forces.

[in important feature of the invention is the single connection throughthe ball and socket joint 29 between the braking unit and the truckframe. By this arrangement, rocking of the truck frame relative to thewheels while the brakes are applied will have no eilect upon theoperation of the brake units, and further, said units are free to movewith the wheels ll relative to the truck frame ll, due to inequalitiesin the track rails II or the like and thereby avoid subjecting the truckframe to stresses which would tend to cause said frame to tip in eitherone direction or the other 9 during braking. In other words, due to thesingle pivotal connection It between the cradle 21 and truck frame II,the operation of the mechanism during braking will have no adverseeifectupon the truck frame, while movement of the truck frame relative to thewheels ll will in no way aifect the operation of the braking unitsduring braking.

It will be noted that since the supply of fluid under pressure to thebrake cylinder devices I! for applying the brakes is controlled by thecentralizing piston 64, the brakes can not be applied before thenon-rotatable elements 22 are moved into concentric relation with therotatable elements 2|, but immediately upon obtaining such relation thebrakes can be applied. This is very desirable in that it ensures promptapplication of brakes Just as soon as the non-rotatable elements aremoved to their concentric braking position.

When it is desired to effect a release of the brakes after anapplication fluid under pressure is vented from the pipe 86 and therebyfrom the centralizing piston chamber 8! and at the same time from thebrake cylinder piston chambers ll through pipes 89 and 94 and saidchamber.

when the pressure acting on the brake cylinder pistons I3 is thusreduced sufliciently, the release springs 88 return said pistons totheir release position, as shown in the drawing, and during suchmovement operate the equalizing levers it to first release the brakingpressure on brake levers l6 urging the non-rotatable elements 22 intofrictional engagement with the rotatable elements 2| and then furthermovement of the equalizing levers 80 operate the connected brake leversIt to move the non-rotatable elements 22 into such spaced relation as tobe disengaged from the respective rotatable elements 2|. This spacingmay be obtained in any desired manner, such for instance as by the useof stop pins 91 provided through the leg portions 32, ll of the supportbars 32 and 34 and so arranged as to be engaged by the adjacent portionsof the inner non-rotatable elements upon movement thereof apredetermined distance away from the adjacent rotatable elements 2|.After the inner non-rotatable elements are moved into contact with thepins 81, further release movement of the connected levers 1 acts throughthe links II to move the outside.

non-rotatable elements 22 a predetermined distance away from therotatable elements 2|.

when the pressure of fluid acting on the con- ;tralizing piston I4 isreduced suiiiciently, spring 68 acting on the piston returns said pistonto its release position which movement acts through the equalizer bar asand connecting rods H to turn the levers I! in such a directional todraw the crossheads II out of their centralizing position back to theirnormal position, in which the rollers t! are disengaged and spaced fromthe sleeves 28 for again permitting movement of the cradle 21 with thetruck frame relative to the axle ll.

As cross-heads I are returned to'their normal position the springsupporting devices ll again become eflective to support the free end ofthe cradle 21 as will be evident.

In effecting a release of the brakes the fluid pressure from the brakecylinders I! is released through pipe I as above described until thecentralizing piston N moves over the brake cylinder port ll on itsreturn to its normal position, after which any fluid pressure stillremaining in the brake cylinders is vented by way of the nonpressurechamber 8! and thence to the atmosphere through the vent passage II.

If desired, both of the braking units on axle Il may be controlled by asingle brake cylinder device instead of being independently controlledby the two brake cylinder devices 82 as above de-.

scribed. A construction embodying this modification is shown in Figs. 8and 9 of the drawings. In the modification a single brake cylinderdevice Ill, disposed to operate in a direction transversely of the trucklike the brake cylinder devices '2 above described, is disposed in thecradle 21 at one side of the axle I. substantially midway between thetop and bottom of the cradle and is supported therein on a bracket illsecured to an desired part of the cradle.

The brake cylinder device I comprises a casing I" containing a piston(not shown) and a piston rod 86 adapted to be operated by said piston.One end of a brake lever III is connected to the piston rod 88 while theopposite end is connected through the medium of a link I ll to one ofthe equalizer levers ll. Another brake lever I" is provided with a yokedend pivotally connected to the brake cylinder casing Ill while theopposite end of said lever is pivotally connected by link I" to theother equalizer lever II. The two levers I01. and II! are connectedtogether intermediate their ends by a link III.

In operation, when the piston rod I of the brake cylinder device I ismoved outwardly of the casing iii in order to effect an application ofthe brakes, the brake lever I is rocked in a clockwise direction, asviewed in Fig. 8, and through the medium of link lit acts to rock thelever iii! in the opposite direction. This rocking movement of thelevers II! and III is transmitted through the links I" to the equalizerlevers l0 and acts to draw said levers towards each other for therebyoperating the brake levers 16 to effect an application of the brakes onthe truck in the same manner as effected by the two brake cylinderdevices 82, above described.

when fluid under pressure is released from the brake cylinder device I"the piston rod It is moved into the casing I" by a release spring (notshown) and this movement acts to draw the connected end of the lever Illtoward the yoked end of the lever ill and due to the connection of linksIll between said levers, the equalizer levers II are moved apart forthereby operating the brake levers II to draw the nonrotatable elements2! out of frictional engagement with the rotatable elements 22, as abovedescribed.

Either of the brake arrangements above described is adapted to beemployed in connection with substantially all conventional type oftrucks used under railway-vehicles to provide eflicient and flexiblebraking thereof. Both arrangements are relatively simple in constructionand so arranged as to be applied to and maintained on a truck withoutany dismantling of the truck.

While two illustrative embodiments of the invention have been describedin detail, it is not my intention to limit its scope to theseembodiments or otherwise than by the terms of the appended claims. I

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is:

l. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently carried on said assembly, saidmechanism comprising a plurality of annular, rotatable friction brakingelements encircling said axle and secured to rotate with said assemblyin concentric relation therewith, annular non-rotatable 2. A brakemechanism for a vehicle truck having a wheel and axle assembly and atruck frame resiliently carried on said assembly, said mechanismcomprising a plurality of annular, rotatable friction braking elementsencircling said axle and secured to rotate with said assembly inconcentric relation therewith, annular non-rotatable friction brakingelements encircling said axle and adapted to frictionally engage saidrotatable elements to effect braking of said assembly, a rigid cradlelike structure having a universal Joint connection with said truck frameand connected to said non-rotatable elements for supporting and holdingsaid non-rotatable elements against r0- tation, and means operativelyconnecting said structure and assembly f r centralizing saidnonrotatable elements with said rotatable elements.

3. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently carried on said assembly, saidmechanism comprising a plurality of annular, rotatable friction brakingelements encircling said axle and secured to rotate with said assemblyin concentric relation therewith, annular non-rotatable friction brakingelements encircling said axle and adapted to frictionally engage saidrotatable elements to effect braking of said assembly, and a' rigidcradle like structure carrying at one end said non-rotatable elementsand cooperative with spaced portions of said assembly to support saidnon-rotatable elements in cooperative. relation with said rotatableelements, and means providing a universal joint connection between saidstructure and truck frame at one side of said assembly,

4. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently carried on said assembly, saidmechanism comprising a plurality of annular, rotatable friction brakingelements encircling said axle and secured to rotate with said assemblyin concentric relation therewith, annular non-rotatable friction brakingelements encircling said axle and adapted to frictionally engage saidrotatable elements to efiect braking of said assembly, a rigid,

cradle like structure having at one side of said assembly a single,universal coupling connection with said truck frame, means connectingsaid non-rotatable elements to said structure for supporting saidnon-rotatable elements and for holding same against rotation, and meansassociated with said structure and cooperative with said assembly forsecuring said non-rotatable elements in cooperative relation with saidrotatable elements.

5. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently carried on said assembly, saidmechanism comprising a plurality of annular, rotatable friction brakingelements encircling said axle and secured to rotate with said assemblyin concentrio relation therewith, annular non-rotatable friction brakingelements encircling said axle and adapted to frictionally engage saidrotatable elements to eflect braking of said assembly, and a rigidcradle like structure carrying at one end said non-rotatable elementsand cooperative with spaced portions of said assembly to support saidnon-rotatable elements in cooperative relation with said rotatableelements, and means providing a universal joint connection between saidstructure and a central transverse portion of said truck frame at oneside of said assembly.

6. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently carried on said assembly, saidmechanism comprising a plurality of annular, rotata-. ble frictionbraking elements encircling said axle and secured'to rotate with saidassembly in concentric relation therewith, annular non-rotatablefriction braking elements encircling said axle and adapted tofrictionally engage said rotatable elements to effect braking of saidassembly, a rigid cradle like structure having a universal joint 7connection with said truck frame and connected to said non-rotatableelements for supporting and holding said non-rotatable elements againstrotation, means for connecting said structure to said assembly in aposition for centralizing said non-rotatable elements with saidrotatable elements, and a brake cylinder device carried by saidstructure and operatively connected to said non-rotatable elements foractuating same.

7. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently carried on said assembly, saidmechanism comprising a plurality of annular, rotatable friction brakingelements encircling said axle and secured to rotate with said assemblyin concentric relation therewith. annular non-rotatable friction brakingelements encircling said axle and adapted to frictionally engage saidrotatable elements to effect braking of said assembly, a rigid, cracLalike structure disposed at one side of said assembly and havingcentrally at one side a universal joint torque connection with a centraltransverse portion of said truck frame and having at the opposite sideoutwardly projecting portions, support rods secured to said outwardlyprojecting portions for supporting said non-rotatable elements and forholding same against rotation, and means associated with said outwardlyprojecting portions cooperative with said assembly for securing saidnon-rotatable elements in cooperative relation with said rotatableelements.

8. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently carried on said assembly, saidmechanism comprising a plurality of annular, rotatable ture to saidassembly for movement therewith for holding said non-rotatable elementsin cooperative relation with said rotatable elements, and fluid pressurecontrolled means carried by said structure and operatively connected tosaid non-rotatable elements for actuating same.

9. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently carried by said assembly, saidmechanism comprising two brake units encircling said axle with one unitadjacent each of the wheels of said assembly, each brake unit comprisingan annular rotatable friction brake element secured to rotate with saidassembly and an annular nonrctatable friction braking element adapted tobe moved into frictional engagement with said rotatable element foreffecting braking thereof, a rigid cradle like structure disposed at oneside of said assembly and comprising aback portion having centrally auniversal joint torque connection with a central transverse portion ofsaid frame, arms projecting from said back portion supporting saidnon-rotatable elements and for holding same against rotation, and meansassociated with said arms and cooperative with said assembly forcentralizing said non-rotatable elements with said rotatable elements.

10. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently carried by said assemblnsaidmechanism comprising a plurality of spaced annular, rotatable frictionbraking elements disposed between the wheels of said assembly inconcentric relation therewith and secured to rotate with said assembly,a plurality of annular, non-rotatable friction braking elements forfrictionally engaging said rotatable elements, said non-rotatableelements encircling said axle and being'capabie of movement in avertical direction-relatively thereto, a rigid cradle like structurehaving at one end a universal joint torque connection with a centraltransverse portion of said truck frame, adjustable means supporting theopposite end of said structure from said truck frame, said structurecarrying said non-rotatable elements and being operative to hold sameagainst rotation, and means associated with said structure andcooperative with said assembly for rocking said structure relative tosaid truck frame about said universal joint connection for centralizingsaid non-rotatable elements with respect to said rotatable elements.

11. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently carried by said assembly, saidmechanism comprising a plurality of spaced annular, rotatablefrictionbraking elements disposed between the wheels of said assenflalyin concentric relation therewith and secured to rotate with saidassembly, a plurality of annular, non-rotatable friction brakingelements-for frictionally engaging said rotatable elements, saidnon-rotatable elements encircling said axle and being capable ofmovement in a vertical direction relatively thereto, a rigid cradlelike'structure having at one end a universal joint torque connectionwith a central transverse portion of said truck frame, adjustable meanssupporting the opposite end of said structure from said truck frame,said structure carrying said non-rotatable elements and being operativeto hold same against rotation, means carried by said structure andcooperativewith said assembly for rocking said structure relative tosaid frame about said universal joint connection for centralizing saidnon-rotatable elements with said rotatable elements, and other meanscarried by said structure and operatively connected to saidnon-rotatable elements for controlling the operation thereof.

12. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently carried by said assembly, saidmechanism comprising a plurality of spaced annular, rotatable frictionbraking elements disposed between the wheels of said assembly incoficentric relation therewith and secured to rotate' with saidassembly, a plurality of annular, non-rotatable friction brakingelements for frictionally engaging said rotatable elements, saidnon-rotatable elements encircling said axle and being capable ofmovement in a vertical direction relatively thereto, a rigid cradle likestruc- .,ture having at one end a universal joint torque connection witha central transverse portion of said truck frame, adjustable meanssupporting the opposite end of said structure from said truck frame,said structure carrying said non-rotatable elements and being operativeto hold same against rotation, means carried by said structure andcooperative-with said assembly for rocking said structure relative tosaid frame about said universal joint connection for centralizing saidnon-rotatable elements with said rotatable elements, a fluid pressurecylinder device carried by said structure operatively connected to said'means for actuating same, and brake cylinder means carried by saidstructure operatively connected to said non-rotatable elements forcontrolling the operation thereof.

13. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently carried by said assembly, saidmechanism comprising a plurality of spaced annular, rotatable frictionbraking elements disposed between the wheels of said assembly inconcentric relation therewith and secured to rotate with said assembly,a plurality of' annular, nonrotatable friction braking elements forfrictionally engaging said rotatable elements, said non-rotatableelements encircling said axle and being capable of movement in avertical direction relatively thereto, a rigid cradle like structure atone side of said assembly comprising a back portion extendingtransversely of and having centrally a universal joint torque connectionwith a central transverse portion of said truck frame, said structurehaving at each of its opposite ends a substantially horizontallyextending portion extending in the direction of the length of the truck,spring means resiliently connecting said horizontally extending portionsof the cradle to said truck frame, support bars extending transverselyof said truck frame and secured to said horizontally extending portionsfor carrying said nonrotatable elements and for holding same againstrotation, said non-rotatable elements being slidable on said bars in thedirection of their length,

means carried by said cradle and cooperative ii? with said assembly forrocking said cradle about said torque connection to centralize saidnon-rotatable elements with said rotatable elements, and brake cylindermeans carried by said cradle operatively connected to said non-rotatableelements for effecting movement thereof into and out of frictionalengagement with said rotatable elements.

14. A brak'e mechanism for a vehicle truck having a wheel and axleassembly and a truck. frame resiliently carried by said assembly, saidmechanism comprising a plurality of spaced annular, rotatable frictionbraking elements disposed between the wheels of said assembly inconcentric relation therewith'and secured to rotate with said assembly,a plurality of annular, non-rotatable friction braking elements forfrictionally engaging said rotatable elements, said non-rotatableelements encircling said axle and being capable of movement in avertical direction relatively thereto, a rigid cradle like structurehaving centrally at one end a universal joint torque connection with acentral transverse portion of said truck frame, and operativelyconnected at the opposite end to said non-rotatable elements forsupporting and holding same against rotation, resilient means connectingsaid opposite end of said structure to said truck frame for supportingsame, means associated with said structure and cooperative with saidassembly for rocking said structure about said torque connectionrelative to said-frame to centralize said non-rotatable elements withsaid rotatable elements; a fluid pressure cylinder device carried bysaid structure and operatively connected to said means for controllingthe operation thereof, lever means carried by said structure operativelyconnected to said non-rotatable elements, and brake cylinder meanscarried by said structure operatively connected to said lever means foractuating said non-rotatable elements.

15. A brake mechanism for a vehicle truck having an oppositely disposedpair of wheels and a frame resiliently supported on 'said wheels, saidmechanism comprising annular means secured to rotate with said pair ofwheels in concentric relation therewith, annular, rotatable frictionbraking elements secured to said annular means in concentric relationtherewith and rotatable therewith, annular non-rotatable frictionbraking elements for frictionally engaging said rptatable elements andbeing capable of movement in a vertical direction relative to saidrotatable elements, a rigid structure comprising a back portion havingcentrally a universal Joint connection with a central transverse portionof said frame and having a plurality of spaced, parallel arms extendingin a substantially horizontal direction, means securing saidnon-rotatable elements to said arms for movement therewith and forholding same against rotation, resilient means connecting said arms tosaid frame for normally supporting said non-rotatable elements formovement with said frame relative to said rotatable elements, meansassociated with said structure and cooperative with said annular meansfor a frame resiliently supported on said wheels, said mechanismcomprising annular means secured to rotate with said pair of wheels inconcentric relation therewith, annular, rotatable friction brakingelements secured to said annular means in concentric relation therewithand rotatable therewith, annular non-rotatable friction braking elementsfor' frictionally engaging said rotatable elements and being capable ofmovement in a vertical direction relative to said rotatable elements, arigid structure comprising a back portion having centrally a universaljoint connection with a central transverse portion of said frame andhaving a plurality of spaced, parallel arms extending in a substantiallyhorizontal direction, and arranged in pairs with one of each pair abovesaid axle and one below said axle, means carried by said arms carryingsaid non-rotatable elements and for holding same against rotation,resilient means connecting certain of said arms to said frame forsupporting said structure and the mechanism carried thereby from saidframe, centralizing means carried by each pair of arms cooperative withsaid annular means to rock said structure relative to said frame forcentralizing said non-rotatable elements with said rotatable elements,and other means carried by said structure for actuating saidnon-rotatable elements.

17. A brake mechanism for a vehicle truck having an oppositely disposedpair of wheels and a frame resiliently supported on said wheels, saidmechanism comprising annular means secured to rotate with said pair ofwheels in concentric relation therewith, annular, rotatable frictionbraking elements secured to said annular means in concentric relationtherewith and rotatable therewith, annular non-rotatable frictionbraking elements for frictionally engaging said rotatable elements andbeing capable of movement in a Vertical direction relative to saidrotatable elements, a rigid structure comprising a back portion havingcentrally a universal joint connection with a central transverse"portion of said frame and having a plurality of spaced, parallel armsextending in a substantially horizontal direction, and arranged in pairswith one of each pair above said axle and one below said axle, meanscarried by said arms carrying said non-rotatable elements and forholding same against rotation, resilient means connecting certain ofsaid arms to said frame for supporting said structure and the mechanismcarried thereby from said frame, centralizing means carried by each pairof arms cooperative with said annular means to rock said structurerelative to said .frame for centralizing said non-rotatable elementswith said rotatable elements, a fluid pressure operative cylinder devicecarried by said structure operatively connected to said centralizingmeans for controlling the operation thereof, a brake cylinder devicecarried by said structure operatively connected to certain of saidnonrotatable elements for controlling the operation thereof, and anotherbrake cylinderdevice carried by said structure operatively connected toother non-rotatable elements for controlling their operation. 7

18. A brake mechanism for a vehicle truck having an oppositely disposedpair of wheels and a frame resiliently supported on said wheels, saidmechanism comprising annular means secured to rotate with said pair ofwheels in concentric relation therewith, annular, rotatable frictionbraking elements secured to said annular means in concentric relationtherewith and rotatable therewith, annular non-rotatable frictionbraking elements for frictionally engaging said rotatable elements andbeing capable of movement in a vertical direction relative to saidrotatable elements, a rigid structure comprising a back portion havingcentrally a universal Joint connection with acentral transverse portionof said frame and having a plurality of spaced, parallel arms extendingin a substantially horizontal direction, and arranged in pairs with oneof each pair above said axle and one below said axle, means carried bysaid arms carrying said non-rotatable elements and for holding sameagainst rotation, resilient means connecting certain of said arms tosaid frame for supporting said structure and the mechanism carriedthereby from said frame, centralizing means carried by each pair of armscooperative with said annular means to rock said structure relative tosaid frame for centralizing said non-rotatable elements with saidrotatable elements, a fluid pressure operative cylinder device carriedby said structure operatively connected to said central-' izing meansfor controlling the operation there of, and a single fluid pressurecylinder device operatively connected to saidnon-rotatable elements foractuating same.

19. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently supported by said assembly, saidmechanism comprising a plurality of annular rotatable friction brakingelements secured to said assembly for rotation therewith, a plurality ofannular, non-rotatable friction braking elements for frictionallyengaging said rotatable elements to brake said assembly, a rigid cradlelike structure carrying at one end said nonrotatable elements and havingat the opposite end a pivotal torque connection with said truck frame,means associated with said structure and cooperative with said assemblyfor holding said non-rotatable elements in cooperative relation withsaid rotatable elements, fluid pressure con trolled brake cylinder meanscarried by said structure, and leverage means pivotally connected withsaid structure operatively connecting said brake cylinder means to saidnon-rotatable elements for controlling the operation thereof.

20. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently supported by said assembly, saidmechanism comprising a plurality of annular rotatable friction brakingelements secured to said assembly for rotation therewith, a plurality ofannular, non-rotatable friction braking elements for frictionallyengaging said rotatable elements to brake said assembly, a rigid cradlelike structure having at one side a pivotal torque connection with acentral transverse portion of said frame and having projecting from eachend of the opposite side a pair of arms, one of each pair disposed abovesaid axle and the other below, rigid parallel members connecting thearms above the axle and below the axle supporting said non-rotatableelements and for holding same against rotation, said non-rotatableelements being slidable on said rigid members, resilient meansconnecting certain of said arms to said truck frame for normallysupporting said structure from said frame and operative to permitrocking of said structure relative to said frame about the torqueconnection therewith for moving said non-rotatable elements to a brakingposition in concentric relation with said r0- 2,a11,sss

tatable elements, centralizing means slidably mounted between each pairof said arms adapted to cooperate with said assembly for rocking saidstructure to move said non-rotatable elements to said braking position,fluid pressure controlled means carried by said structure andoperatively connected to'said centralizing means for actuating same, andbrake cylinder means also carried by said structure and operatively.connected to said non-rotatable elements for actuating same.

21. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently supported on said assembly. saidmechanism comprising a sleeve secured to androtatable with said axle,said sleeve having an annular flange and at one side of said flange acylindrical centering portion concentric with said wheels, an annularrotatable friction braking element secured to said flange for rotationwith said wheels, an annular non-rotatable friction braking elementadapted to frictionally engage said rotatable element for braking saidwheels, a cradle pivotally connected at one end to said truck frame atone side of said axle and carrying at the opposite end saidnon-rotatable element, means resiliently supporting said opposite end ofsaid cradle from said truck frame. centering means carried by saidcradle adapted to be moved into engagement with the cylindricalcentering portion of said sleeve for moving said non-rotatable elementrelative to said frame into concentric braking relation with saidrotatable element, and means connected to said centering means forcontrolling the operation thereof.

22. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently supported on said assembly, saidmechanism comprising an annular, rotatable friction braking elementsecured 'to rotate with said assembly, a non-rotatable friction brakingelement adapted to frictionally engage said rotatable element foreffecting braking thereof, means for supporting said non-rotatableelement from said frame and operable to permit movement thereof relativeto said frame to a braking position with respect to said rotatableelement, centralizing means connected to said non-rotatable elementoperative to eflect movement of said non-rotatable element to saidbraking position, and means separate from and con trolled by saidcentralizing means and operable to move said non-rotatable element intobraking engagement with said rotatable element.

23. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently supported on said assembly, saidmechanism comprising an annular, rotatable friction braking-elementsecured to rotate with said assembly, a non-rotatable friction brakingelement adapted to frictionally engage said rotatable element foreffecting braking thereof, means for supporting said non-rotatableelement from said frame and operable to permit movement thereof relativeto said frame to a braking position with respect to said rotatableelement, brake control means for moving said nonrotatable element intobraking engagement with said rotatable element, and centralizing meansconnected to said non-rotatable element and operative independently ofsaid brake control means to effect movement of said non-rotatableelement to said braking position and to delay the operation of saidbrake control means until after said braking position is obtained.

24. A brake mechanism for a vehicle truck having a wheel and axleassembly and a truck frame resiliently supported on said assembly,

said mechanism comprising an annular rotatable friction braking elementsecured to rotate with said assembly, a non-rotatable friction brakingelement adapted to frictionally engage said rotatable element foreffecting braking thereof, means for supporting said non-rotatableelement from said frame and operable to permit movement thereof relativeto said frame to a 'braking position with respect to said rotatableelement, brake control means operable by fluid under pressure for movingsaid non-rotatable element into braking engagement with said rotatableIelement, and a centralizing cylinder device operable by fluid underpressure to move said non-rotatable element to said braking position andto then supply fluid under pressure to said brake control means foractuating same.

25. A brake mechanism for a wheel and axle assembly of a railway vehicletruck having a resiliently supported truck frame, said mechanismcomprising adjacent each of the wheels of said assembly an annularrotatable friction braking element encircling said axle and secured tothe wheel for rotation therewith, a non-rotatable friction brakingelement for frictionally engaging each of the rotatable elements tobrake said assembly, a rigid structure carrying said nonrotatableelements and having at one side of said assembly a single pivotalsupport connection with said frame, means for providing a two pointsupport for said structure on spaced portions of said assembly forsecuring said nonrotatable elements in braking relation with saidrotatable elements, brake cylinder means carried by said structure andoperatively connected to said non-rotatable elements for actuating same,and lever means carried by said structure and said brake cylinder meansand non-rotatable elements.

CLYDE C. FARMER.

